Re: [PATCH v10 06/11] usb: dwc3: qcom: Refactor IRQ handling in QCOM Glue driver

[Krishna Kurapati PSSNV]

On 8/8/2023 5:20 PM, Konrad Dybcio wrote:
> On 8.08.2023 10:32, Krishna Kurapati PSSNV wrote:
> >   +
> > > > +enum dwc3_qcom_phy_irq_identifier {
> > > > +    HS_PHY_IRQ = 0,
> > > > +    DP_HS_PHY_IRQ,
> > > > +    DM_HS_PHY_IRQ,
> > > > +    SS_PHY_IRQ,
> > > >    };
> > >
> > > This enum is unused.
> >
> > Hi Bjorn,
> >
> >   I didn't use the enum directly, but used its members in the get_port_irq call below.
> >
> > > [..]
> > > > +static int dwc3_get_acpi_index(const struct dwc3_acpi_pdata *pdata, int irq_index)
> > > > +{
> > > > +    int acpi_index = -1;
> > > > +
> > > > +    if (!pdata)
> > > > +        return -1;
> > > > +
> > > > +    if (irq_index == DP_HS_PHY_IRQ)
> > > > +        acpi_index = pdata->dp_hs_phy_irq_index;
> > > > +    else if (irq_index == DM_HS_PHY_IRQ)
> > > > +        acpi_index = pdata->dm_hs_phy_irq_index;
> > > > +    else if (irq_index == SS_PHY_IRQ)
> > > > +        acpi_index = pdata->ss_phy_irq_index;
> > >
> > > It looks favourable to put these in an array, instead of having to pull
> > > them out of 4 different variables conditionally.
> > >
> > > > +
> > > > +    return acpi_index;
> > > > +}
> > > > +
> > > > +static int dwc3_get_port_irq(struct platform_device *pdev, u8 port_index)
> > > > +{
> > > > +    struct dwc3_qcom *qcom = platform_get_drvdata(pdev);
> > > > +    bool is_mp_supported = (qcom->data->num_ports > 1) ? true : false;
> > > > +    const struct dwc3_acpi_pdata *pdata = qcom->acpi_pdata;
> > > > +    char *disp_name;
> > > > +    int acpi_index;
> > > > +    char *dt_name;
> > > > +    int ret;
> > > > +    int irq;
> > > > +    int i;
> > > > +
> > > > +    /*
> > > > +     * We need to read only DP/DM/SS IRQ's here.
> > > > +     * So loop over from 1->3 and accordingly modify respective phy_irq[].
> > > > +     */
> > > > +    for (i = 1; i < MAX_PHY_IRQ; i++) {
> > > > +
> > > > +        if (!is_mp_supported && (port_index == 0)) {
> > > > +            if (i == DP_HS_PHY_IRQ) {
> > > > +                dt_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "dp_hs_phy_irq");
> > > > +                disp_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "qcom_dwc3 DP_HS");
> > > > +            } else if (i == DM_HS_PHY_IRQ) {
> > > > +                dt_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "dm_hs_phy_irq");
> > > > +                disp_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "qcom_dwc3 DM_HS");
> > > > +            } else if (i == SS_PHY_IRQ) {
> > > > +                dt_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "ss_phy_irq");
> > > > +                disp_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> > > > +                    "qcom_dwc3 SS");
> > Bjorn, Konrad,
> >
> > If we are to remove this repetitive loops, we might need to make a 2D array for all of Dp/Dm/Ss interrutps and make a global array of names to be used for irq lookup and use them to reduce the if-else-if stuff here. If that is fine, I can make those changes, else I would like to stick to this approach for now because if we don't add the global array of names, prepping them seperately for dp/dm/ss would again lead us to making if-else loops like above.
> >
> > Please let me know your thoughts on this.
> Can we not just reuse the associated interrupt-names from the devicetree
> if present?
Hi Konrad,

 Thanks for the comments but one more confirmation.
We can read the interrupts from DT but I believe the compatible would 
still need to stay. We need the num_ports information not just for 
registering interrupts but for modifying the pwr_event_irq registers 
during suspend/resume. If we rely on the interrupts to find the number 
of ports, the user is free to remove any IRQ and we might end up in a 
situation where glue and core are not having same view of how many 
number of ports present. So I believe its best to keep the compatible 
and get num_ports info from there and rely on reading interrupt-names to 
get interrupts cleanly. Can you let me know your view on the same.

Regards,
Krishna,